There is a general tendency to miniaturize the optics and electronics of image-sensing apparatuses with regard to their surface areas, or two-dimensional extensions, and with regard to their thicknesses and/or their overall heights, which result from the thicknesses of the optical elements and the thicknesses of the sensor elements and from the distance between the optical element and the respective image sensor. As the level of miniaturization increases, requirements placed upon adjustment of the optical elements relative to the corresponding sensor elements with regard to their mutual distances and mutual rotations increase as well.
At the same time, it is desirable to be able to employ optical elements having most varied optical properties also in such miniaturized optoelectronic systems so as to be able to realize—in addition to classic photography—light-field photography or spectral decomposition of light, for example.
Previous structural design technologies, in particular for light-field photography, have been based on discrete components wherein each image sensor is individually provided with the optical element specified for it. Adjustment is effected via precision-mechanical adjustment apparatuses, with which height adjustment (z direction) and the lateral position (x-y direction) may be set permanently or reversibly. However, the level of accuracy of the adjustment here is limited, e.g. is in a range of above 20 μm.
A different approach to adjustment and fixing consists in utilizing shrinkage of a UV-curing (UV=ultraviolet) adhesive for highly precise repositioning. Said adhesive is employed, for example, for adjusting glass fibers in front of laser diodes. Adjustment is achieved in that UV irradiation is adapted such that the glass fiber is fixed in place in as ideal a position as possible in relation to the laser diode.
Another possibility consists in employing microactuators as a dynamic positioning apparatuses so as to optimally position the optical element in relation to the sensor element.